When apartment, Villa or house have two entrances, it is not always clear where to call. Electrosonic, which tells of the Bulgarian journal “Radio Television Electronics”, rid us of this inconvenience. When you press the button S2, relay K1 cambiocorsa their contact close. Simultaneously, lamp H2 lights up. Call H3 will beep until until the capacitor C1 is not charged up to the supply voltage. To signal again, the button S2 is released, and the capacitor C1 is discharged through the winding of the call. H2 lamp continues to burn as long as the supply circuit of the relay K1 will not open with button S3.CALL, OPEN THE DOOR!
When apartment, Villa or house have two entrances, it is not always clear where to call. Electrosonic, which tells of the Bulgarian journal “Radio Television Electronics”, rid us of this inconvenience. When you press the button S2, relay K1 cambiocorsa their contact close. Simultaneously, lamp H2 lights up. Call H3 will beep until until the capacitor C1 is not charged up to the supply voltage. To signal again, the button S2 is released, and the capacitor C1 is discharged through the winding of the call. H2 lamp continues to burn as long as the supply circuit of the relay K1 will not open with button S3.
Who has not experienced the beneficial effects of the measuring noise of the rain forests, the sea… the sound relaxes and soothes. That is why the simulator of the surf, which we offer to readers, is used as a stimulant of sleep in insomnia. Generator “of the sea” is easy to manufacture and configure, does not contain scarce radio parts and accessible even for novice radio Amateurs. Here’s how it works.
Automatic devices that produce sound and light signals, are widely used in various designs and models. Usually auto-switch performs the multivibrator, the control of sound or light emitter (call, dynamic head, incandescent, etc.). These devices contain more transistors and a dozen resistors and capacitors.
About code locks wrote more than once. However, most of them are difficult to repeat. Design suggested by our Bulgarian friends (the journal “Radio Television Electronics”), devoid of this shortcoming. For opening this lock simply insert the key and complete the circuit with the resistor R1 a certain value (it is mounted in the housing of the key). If the resistance will be different from that specified on the schematic, the relay does not work and the lock will not unlock.
Induction coil, in the last century invented Rumkorem, and is now used in experiments in physics. But now it is not fully satisfy the requirements of physical experiment creates interference, does not regulate the high voltage. consumes battery power, and feed the coil directly from the mains AC is impossible. We offer you to equip physical classrooms modernized version of the instrument developed on the basis of electronics.
In a previous article under the heading “electronics for beginners” (see “M-K” № 8, 1979) we understand how magnetic field is formed it Turned out that, in particular, generates supplied to the coil (solenoid) electric current. The same field with a certain force acts on it carried to the magnet. But the magnet with the same force acts on the wire, which carries current. On the phenomenon of the interaction of electric current and magnet based electric motors (electric motors).
Time relay, the readers, used in the automation devices in the workplace and at home. The device is simple in design, has small dimensions, is reliable in operation, but its main feature — a large range of exposures.
electrical Work on a modern industrial enterprise impossible without measuring instruments, many of them are very complex.
In the sixth issue of our magazine in 1974 we told about the device “Pulse” for the control of knowledge of students. Practice operating the machine created by the participants NTTM Donetsk Polytechnic Institute, as well as the feedback from readers has convinced authors of the need to improve the design.